Initial configuration for an OpenTelemetry Collector

Co-authored-by: Benjamin Blattberg <[email protected]>
Co-authored-by: Drew Sessler <[email protected]>
Co-authored-by: Tony Landreth <[email protected]>

Author: 4 people

internal/collector/config.go

@@ -0,0 +1,93 @@
+// Copyright 2024 Crunchy Data Solutions, Inc.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package collector
+
+import (
+	"k8s.io/apimachinery/pkg/util/sets"
+	"sigs.k8s.io/yaml"
+)
+
+// ComponentID represents a component identifier within an OpenTelemetry
+// Collector YAML configuration. Each value is a "type" followed by an optional
+// slash-then-name: `type[/name]`
+type ComponentID string
+
+// Config represents an OpenTelemetry Collector YAML configuration.
+// See: https://opentelemetry.io/docs/collector/configuration
+type Config struct {
+	Exporters  map[ComponentID]any
+	Extensions map[ComponentID]any
+	Processors map[ComponentID]any
+	Receivers  map[ComponentID]any
+
+	Pipelines map[PipelineID]Pipeline
+}
+
+// Pipeline represents the YAML configuration of a flow of telemetry data
+// through an OpenTelemetry Collector.
+// See: https://opentelemetry.io/docs/collector/configuration#pipelines
+type Pipeline struct {
+	Extensions []ComponentID
+	Exporters  []ComponentID
+	Processors []ComponentID
+	Receivers  []ComponentID
+}
+
+// PipelineID represents a pipeline identifier within an OpenTelemetry Collector
+// YAML configuration. Each value is a signal followed by an optional
+// slash-then-name: `signal[/name]`
+type PipelineID string
+
+func (c *Config) ToYAML() (string, error) {
+	const yamlGeneratedWarning = "" +
+		"# Generated by postgres-operator. DO NOT EDIT.\n" +
+		"# Your changes will not be saved.\n"
+
+	extensions := sets.New[ComponentID]()
+	pipelines := make(map[PipelineID]any, len(c.Pipelines))
+
+	for id, p := range c.Pipelines {
+		extensions.Insert(p.Extensions...)
+		pipelines[id] = map[string]any{
+			"exporters":  p.Exporters,
+			"processors": p.Processors,
+			"receivers":  p.Receivers,
+		}
+	}
+
+	b, err := yaml.Marshal(map[string]any{
+		"exporters":  c.Exporters,
+		"extensions": c.Extensions,
+		"processors": c.Processors,
+		"receivers":  c.Receivers,
+		"service": map[string]any{
+			"extensions": sets.List(extensions), // Sorted
+			"pipelines":  pipelines,
+		},
+	})
+	return string(append([]byte(yamlGeneratedWarning), b...)), err
+}
+
+// NewConfig creates a base config for an OTel collector container
+func NewConfig() *Config {
+	return &Config{
+		Exporters: map[ComponentID]any{
+			// TODO: Do we want a DebugExporter outside of development?
+			// https://pkg.go.dev/go.opentelemetry.io/collector/exporter/debugexporter#section-readme
+			DebugExporter: map[string]any{"verbosity": "detailed"},
+		},
+		Extensions: map[ComponentID]any{},
+		Processors: map[ComponentID]any{
+			// https://pkg.go.dev/go.opentelemetry.io/collector/processor/batchprocessor#section-readme
+			OneSecondBatchProcessor: map[string]any{"timeout": "1s"},
+			SubSecondBatchProcessor: map[string]any{"timeout": "200ms"},
+
+			// https://pkg.go.dev/github.com/open-telemetry/opentelemetry-collector-contrib/processor/groupbyattrsprocessor#readme-compaction
+			CompactingProcessor: map[string]any{},
+		},
+		Receivers: map[ComponentID]any{},
+		Pipelines: map[PipelineID]Pipeline{},
+	}
+}

internal/collector/config_test.go

@@ -0,0 +1,33 @@
+// Copyright 2024 Crunchy Data Solutions, Inc.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package collector
+
+import (
+	"testing"
+
+	"gotest.tools/v3/assert"
+)
+
+func TestConfigToYAML(t *testing.T) {
+	result, err := NewConfig().ToYAML()
+	assert.NilError(t, err)
+	assert.DeepEqual(t, result, `# Generated by postgres-operator. DO NOT EDIT.
+# Your changes will not be saved.
+exporters:
+  debug:
+    verbosity: detailed
+extensions: {}
+processors:
+  batch/1s:
+    timeout: 1s
+  batch/200ms:
+    timeout: 200ms
+  groupbyattrs/compact: {}
+receivers: {}
+service:
+  extensions: []
+  pipelines: {}
+`)
+}

internal/collector/naming.go

@@ -0,0 +1,10 @@
+// Copyright 2024 Crunchy Data Solutions, Inc.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package collector
+
+const CompactingProcessor = "groupbyattrs/compact"
+const DebugExporter = "debug"
+const OneSecondBatchProcessor = "batch/1s"
+const SubSecondBatchProcessor = "batch/200ms"

internal/naming/names.go

@@ -18,6 +18,8 @@ import (
 )
 
 const (
+	ContainerCollector = "collector"
+
 	// ContainerDatabase is the name of the container running PostgreSQL and
 	// supporting tools: Patroni, pgBackRest, etc.
 	ContainerDatabase = "database"